The present inventions relate generally to internal multi-band antennas, and more particularly to dual-band internal antennas for dual-band communications devices and combinations thereof.
As cellular telephone handsets continue to be reduced in size, consumers expect phones with either non-retractable antennas or internal antennas that are not at all visible. In general, retractable and stubby antennas work together with a ground plane provided the antenna is located away from the ground plane. When retractable and stubby antennas are located near the ground plane, the input impedance drops to very low values. Stubby antennas do not work well generally in close proximity of a ground plane.
Internal antennas are known generally as disclosed, for example, in U.S. Pat. No. 5,926,139 entitled xe2x80x9cPlanar Dual Frequency Band Antennaxe2x80x9d. More particularly, the dual frequency antenna of U.S. Pat. No. 5,926,139 includes a ground plane separated by a dielectric from a planar radiating element having first and second inverted F-antenna portions joined by an interconnecting portion, which is coupled by to the ground plane by a ground pin. A feed pin coupled to the radiating element extends through the ground plane by an insulating via.
The various aspects, features and advantages of the present invention will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description of the Invention with the accompanying drawings described below.